MARIC Topology optimization of Oil Tanker Structures in

MARIC Topology optimization of Oil Tanker Structures in Cargo Tank Region QIU Weiqiang, GAO Chu, SUN Li, LUO Renjie Speaker: GAO Chu October 2016

Content Proposal for a VLCC with one center line longitudinal bulkhead Introduction to structure optimization techniques Definition of Structural Model, boundary conditions and load patterns FEA Topology results discussion Conclusions 2 MARIC

Hull structure of VLCC and Suezmax size oil tanker Typical transverse section of a VLCC Typical transverse section of a Suezmax size oil tanker VLCC with one C. L. BHD 3 MARIC

Tank arrangements of proposed VLCC and traditional one Traditional VLCC with one C. L. BHD 4 MARIC

Important issues to be aware of Shear Strength Stringer Design Local Strength 5 MARIC

The “GREAT STONE BRIDGE” 7. 3 m An Chi Ch'iao the Great Stone Bridge Chao Hsien, Hobei, China Sui Dynasty , AD 569 -617, Li Chun Master Builder 6 37. 02 m

Hull Structure Optimization Design Production Cost Topology Optimization Structure Capability Hull Structure Optimization Design Size Optimization 7 Shape Optimization MARIC

Continuum Topology Optimization Methods Homogenization method SIMP （Solid Isotropic Microstructure with Penalty) method ESO/BESO (Evolutionary /Bi-directional Evolutionary Structural Optimization) method ICM (Independent Continuous Mapping) method Level Set method “Killed” element Perimeter Method … 8 SIMP BESO MARIC

Basic Topology Optimization Procedure START FEA Sensitivity Filter Scheme Construct a new design No Converged ? Yes END 9 MARIC

Structures to be optimized 10 MARIC

Loading Patterns and model constraints Load Cases 45 Location δx Translation δy δz Aft End Cross section - Rigid Link Independent point Cross section - Fix Rigid Link θx Rotation θy θz Rigid Link - - Fix End beam Fore End Crosssection - Rigid Link Independent point Fix Intersection of CL&IB Fix Cross section Where: - no constraint applied (free) 11 Rigid Link - - Fix - - End beam MARIC

Problem Statement “Killed” element Solid Empty SIMP 12 BESO MARIC

Structures to be optimized Transverse frames Horizontal Stringers Non-designable Designable 13 MARIC

Structures to be optimized Separated 14 MARIC

Resulting topology of all loading patterns 15 MARIC

Resulting topology of typical transverse frame (all loading patterns) SIMP 16 BESO MARIC

Resulting topology of B 3 by SIMP method 17 MARIC

Iteration steps in SIMP process without loading patterns B 3 & B 11 18 Iteration 0 MARIC

Iteration steps in SIMP process without loading patterns B 3 & B 11 19 Iteration 1 MARIC

Iteration steps in SIMP process without loading patterns B 3 & B 11 20 Iteration 10 MARIC

Iteration steps in SIMP process without loading patterns B 3 & B 11 21 Iteration 20 MARIC

Topology Optimized Trans. Frames & H. Stringers 22 Final solution (Iteration 67) MARIC

Optimum topology by SIMP 23 MARIC

Optimum topology by BESO 24 MARIC

Optimum topology of typical transverse frame by SIMP method 25 MARIC

Optimum topology of typical transverse frame by BESO method 26 MARIC

Optimum topology of typical transverse frame 27 MARIC

Optimum topology of typical horizontal stringers by SIMP & BESO method SIMP 28 BESO MARIC

Optimized topology & new designs 01 SIMP 02 BESO 29 MARIC

Optimized topology & new designs SIMP 30 BESO MARIC

Shape/size optimization Vertical Girder Web Height Optimization 31 Horizontal Stringer Web Height Optimization Deck Transverse Web Height Optimization Size Optimization 01 02 Rule Check Nonlinear FEA Elastic column buckling Elastic torsional buckling Elastic column / torsional buckling Elasto-plastic behavior of the primary support member

BESO/SIMP optimum topology comparisons 32 Compared subjects SIMP BESO Traditional VLCC Surface areas of typical transverse frames (m 2) 575. 8 643. 3 731. 8 78. 7% 87. 9% Averaged weight of typical transverse webs (ton, except for wash BHD) 100. 8 111. 3 143. 1 70. 4% 77. 8% Structural weight per meter in cargo hold (ton) 111. 75 112. 55 127. 3 87. 8% 88. 4% 800 160 700 140 600 120 500 100 400 80 300 60 200 40 100 20 0 Comparison(%) 0 Surface area Averaged weight Weight per meter MARIC

Comparison between VLCC with one C. L. BHD and traditional one Transverse section arrangements of VLCC with one C. L. BHD 33 Transverse section arrangements of Traditional VLCC MARIC

Comparison between VLCC with one C. L. BHD and traditional one Horizontal stringer arrangements of VLCC with one C. L. BHD 34 Horizontal stringer arrangements of Traditional VLCC MARIC

Topology optimization with 3 D elements 35 MARIC

Topology optimization with 3 D elements 36 MARIC

Topology optimization with 3 D elements 37 MARIC

Application on other tankers New/Old transverse section design of Suezmax oil tanker 38 MARIC

Application on other tankers New/Old transverse section design of Aframax oil tanker 39 MARIC

Applications Vertical web end of a Aframax size oil tanker 40 MARIC

Conclusions New structural design of a VLCC is proposed Optimum topology of the VLCC with one C. L. BHD calculated and discussed Problems encountered during the optimization procedure Limitations of present optimization tools Issues to be resolved in the future 41 MARIC

THANKS 中国船舶及海洋 程设计研究院 MARINE DESIGN & RESEARCH INSTITUTE OF CHINA 42